Due to these factors there is a need to find alternative MSC sources where there is a potentially larger yield of cells. Initial techniques involved the development of

devices to concentrate MSCs from large volumes of ICBM aspirate by centrifugation [10]— and such devices are available in the clinic. The implantation of 50,000 uncultured MSCs/CFU-Fs by concentrating selleck up to 300 ml of ICBMA has shown an improvement of fracture healing in one study [10]. However, it is not always possible to obtain such large amounts of ICBMA. The enzymatic digestion of adipose-rich connective tissues such as fat has been proposed as an alternative strategy, with authors reporting the liberation of 500-fold more MSCs per gram of tissue when compared with ICBMA [11]. GSI-IX mw Lipoaspiration however cannot be performed for every orthopedic patient and the “quality” of lipoaspirate-derived MSCs for bone repair applications remains debatable [12], [13], [14], [15], [16] and [17]. Multipotential stromal cells have previously been shown to be present in the intramedullary cavity of long bones in humans [18]. However, this has been largely ignored as a source of MSCs for bone regeneration. In contrast, the harvesting of long-bone BM has been practiced on rat [19], mouse [20], rabbit [21], [22] and [23]

and pig [24] and [25] and is probably the most prevalent research method of isolating MSCs from animals. Analogous to other adipose-rich tissues, it may be hypothesized many that the intra-medullary (IM) contents of long bones contain large numbers of MSCs. Unlike peripheral fat tissues, the MSCs are present in a bone related micro-environment and may potentially exhibit good intrinsic osteogenic capabilities. This is supported by early pioneering findings documenting a strong in vivo osteogenic capacity of adipogenic marrow cells [23]. This study explored the aspirated contents from the IM cavities

of long bones, which are frequently accessed by the trauma/orthopaedic surgeon, as a source of MSCs in comparison to the ‘gold standard’ iliac crest aspirated source. We used colony-forming fibroblast (CFU-F) assay [26] and flow cytometry for CD45−/lowCD271+ fraction [27], [28] and [29] to enumerate MSCs and compared their frequency with donor-matched ICBM aspirates. We also used functional in vitro assays for MSC expansion and differentiation, to demonstrate that MSCs from IM cavities of long bones were equal or superior to their ICBMA counterparts. These findings should permit the development of novel one-step MSC harvesting procedures for bone repair augmentation in fracture patients. Approval for these studies was obtained from the Leeds Teaching Hospital NHS trust ethics committee, with all patients providing informed consent.